Circuit protecting device



Oct. 15, 1935. H. A. TRlPLx-:TT 2,017,639

CIRCUIT PROTECTING DVICE Filed June 21, 1955 Patented Oct. 15, 1935 UNITED STATES ATENT OFFICE CIRCUIT PROTECTING DEVICE poration of Delaware Application June 21, 1933, Serial No. 676,913

27 Claims.

This invention relates to circuit protecting devices.

It is now common practice in electric power and substation installations to place the busses comparatively close together in order to conserve installation space. The busses and leads are in- Sulated for their entire length. In such installations the application of conventional forms of protective combinations, such as fuses and resistor mountings, are impractical because of the exposed parts and because or" the necessity of using insulated tongs for insertion or removal of the fuses.

It is one of the objects of the present invention to provide a compact, dust-proof, insulated assembly containing a current limiting resistor and a fuse, which is particularly a-dapted for use in a system employing insulated busses.

It is a further object of the present invention to provide a compact assembly such as set forth above, which will provide adequate dielectric strength with minimum space requirements and wherein the fuse can be inserted or removed without the use of insulated tongs.

My improved assembly includes a door on which the fuse is mounted so that closing .or opening of the door inserts or removes the fuse from the circuit. The door is provided with a handle to allow a positive grip with rubber gloves, and arranged so `that an o perator cannot get his fingers caught in the handle.

It is a still further object of the present invention to provide an improved contact structure which hol-ds the fuse and is itself gripped to hold the door in position.

The attainment of the above and further objects of the present invention will be apparent from the following specication, taken in conjunction with the accompanying drawing forming a part thereof.

In the drawing:

Figure 1 is a iront view of my improved protective device;

Figure 2 is a longitudinal sectional View taken along the line 2-2 of Figure 1; and

Figure 3 is a sectional View taken along the line S-3 of Figure 2.

Reference may now be had more particularly 50 to the drawing. The protective device is mounted within a tube l, of impregnated fiber or other suitable insulation. The ends of the tube are closed by metallic end bells or caps 2 and 3 through which extend similar porcelain bush- 55 ings 4 and 5 which form liquid-tight seals with (Cl. ZOO- 120) the end caps. Brackets 6 6 are formed integral with the end caps for mounting the unit.

The circuit is .extended through the bushing by means ci a conductor l which terminates in a copper bracket 8 on the under side of a cast 5 iron ntting Si, cemented or otherwise secured to the bushing. A tube it, of the material known as Bakelite comprising a phenolic condensation product, is interposed between the conductor 'e' and the bushing t in order to facilitate taping 10 of the terminal. The tape has been indicated at ii on the lower lead-in connection in Figure 2. While have here shown only one connection taped itis to be understood that taping is also applied to the other connection. A termi- 15 nal clip i2 is mounted upon the copper bracket 8. The circuit connection through the procelain bushing 5 extends, in a manner similar to that through the bushing li, to one side of a resistor unit is. The resistor comprises a glass enclosed 20 unit of any preferred construction, such as is shown, for example, in the pending application oi Nicholas J. Conrad, Serial No. 244,015, filed Eecember 31, 1927, or in the application of myself and Allan Ramsey, Serial No. 611,850, Iiled 25 May 17, i932. A copper bracket 8', of a construction similar to the bracket 8, is mounted on the resistor unit iii and comprises a support for a terminal clip l2', oi a construction similar to the terminal l2. While I have here shown a 30 resistor unit connected to the lower bushing, it is to be understood that the unit may be connested to the upper bushing, or one or more resistance units ifi may be connected to both bushings. 35

The front oi the tube i is provided with a rectangular oblong opening 2t which is adapted t0 be closed by a removable door 2t of suitable insulating material, such as the material known as Bakelite comprising a phenolic condensation 40 product. The door or closure 2i is provided with a handle 22 formed integrally therewith. The handle is a glove type grip handle and has a web 23 to prevent an operator from inadvertently catching his fingers within the handle. Upper 45 and lower fuse clips Z5-2t are secured to the closure 2i and are adapted to receive the end ferrules of a fuse 2e. The lower end of the fuse bears against a stop The fuse is preferably, although not necessarily, of the type known as the Schweitzer & Conrad fuse. One form of this type of fuse is shown in the United States Patent to Nicholas J. Conrad, No. 1,834,578, issued December l, 1931. Another suitable form of fuse is shown in Patent No. 1,215,722, of February 17,

' the clips 24 to the outside of the housing.

1917, to which reference may be had. The fuse shown in said latter patent has a resistor incorporated therein, hence the resistor unit I4 may be dispensed with when such a fuse is used.

The fuse clips 24%24 embrace the end ferrules of the fuse in the manner illustrated in Figure 3, and exert a spring pressure thereagainst. The clips I2-I2' are approximately C-shaped, with guiding wings on the free extremities or Contact portions for guiding the fuse clips 24 into place between the free extremities or contact portions. The contact portions of the clips Iii-I2 which bear against the Contact springs Ztl- 2d are wedge shaped surfaces, the apices providing line contact with the fuse holding clips 2d- 24. The inner flanking surfaces cooperate with the projections 21--2'I to provide a snap action.

The clips I2-I2 thereby permit the fuse clips 24-24 to be introduced from an angular position on either side of direct frontal alignment. Even though the fuse clips be introduced at a slight angle clockwise or counterclockwise from the position shown in Figure 3, the guiding wings tend to bring the cooperating parts I2-24 into eifective register. Then, as the parts are further brought together by pushing on the handle one of the projections 21 will slide over the hill or projection of the spring clip I2', tending thereby to draw the projection further inwardly. The edges of the tongues 28-28 limit the extent oi angular displacement. Then, as the handle 22 is further pushed in, the other projection 2l rides over the hill formed on the free extension of the spring clip I2', also tending to pull the same further inward. As the edges of the web: or tongues 28-28 are tapered, this inward thrust of springs I2-I2 upon the pairs of projections 2121 on each fuse clip 24 causes the whole cover member to snap into place substantially accurately in alignment with the opening and overlapping the edges of the same. When the door 2| is in its closed position the terminal clips I2-I2 embrace the fuse clips 24 and exert a spring pressure against the fuse clips, tb by increasing the pressure of the fuse clips aga t the fuse ferrules. Projections ill- 2l on the fuse clips are engaged by the terminal clips I2-I2 to hold the door 2I in its closed position, and serve to produce a snap action during closure. I'apered tongues or webs 28-28 are formed at the top and bottom of the inner side of the door i!! and serve to increase the leakage distance from They also serve as guides during closure, so that the clips 24 will be exactly opposite the clips IIL-I2' although not necessarily squarely in frontal alignment with said clips I2--I2 when they rst engage them. The upper and lower ends of the sleeve or tube I are not slotted. Hence, they retain the full hoop strength of the original sleeve. These ends are further reinforced by being tele scoped inside the circular cylindrical flanges of the head flanges 2 and 3.

From the above description it is apparent that I have provided a protective device which is simple and compact in construction. The porcelain bushings, the fuse, and the resistor unit are all in longitudinal alignment to provide a simple compact arrangement which is adequately insu lated and adapted for use in connection with insulated busses or the like, and is particularly adapted for small power transformer or static condenser protection. No venting of the housing is necessary, inasmuch as the fuse cap does not blow off. because the resistor limits the shortcircuit current to a value below that at which blowing olf pressures are generated. The unit may be mounted horizontally or vertically, or on a flat surface. The brackets 8-6 are arranged for mounting on a pipe that extends parallel to 5 the tube I, as illustrated, or for mounting on separate pipes that extend at right angles to the mounting pipe shown in Figure 2, or for mounting on flat surfaces.

In compliance with the requirements of the 10 patent statutes I have herein shown and described a preferred embodiment of my invention. It is, however, to be understood that the invention is not limited to the precise construction herein shown, the same being merely illustrative 15 of the principles of my invention.

What I consider new, and desire to secure by Letters Patent, is:

l. In combination, a tubular casing of insulation, closures for the ends thereof including 20 aligned insulating bushings, a current limiting resistor mounted at one end on one bushing and having a terminal clip at its other end, a terminal clip at the end oi the other bushing, and a circuit interrupting device between the two 25 terminal clips.

2. In combination, a tube of insulation, metallic end pieces closing the ends thereof, bushings extending into the tube through the end pieces, said tube having opening in the periphery 3o thereof, a door closing the opening, a. fuse mount-- ed on. said door, and a resistor unit mounted within the tube of insulation, said resistor unit and fuse being connected in series and in alignment between the bushings. 3,',

3. In combination, a. tubular casing, end pieces closing the ends thereof and including insulating bushings, an enclosed resistor unit mounted at one end on one of the bushings and having a terminal clip at its other end, a terminal clip at o the end of the other bushing, said tubular casing having an opening therein between the two clips,

a closure for the opening, and a` fuse mounted on the closure and receivable between the two clips, said fuse, resistor unit and insulating bushing be- 45 ing in alignment.

4. In combination, a tubular casing, end pieces closing the ends thereof and including insulating bushings, an enclosed resistor unit mounted at one end on one of the bushings and having a 50 terminal clip at its other end, a terminal clip at the end of the other bushing, said tubular casing having an openinU therein between the two clips,

a closure for the opening, and a fuse mounted on the closure and receivable between the two clips, 55 said fuse, resistor unit and insulating bushing being in alignment, said tubular casing and said closure being of insulation, and said closure having a glove type grip handle.

5. In combination, a tube of insulation, metal lic end pieces closing the ends thereof, insulating bushings extending into the tube through the end pieces, a resistor unit mounted at one end on one bushing and having a terminal clip at its other end, a terminal clip at the end of the other bushing, said tube having an opening in the periphery thereof, a door closing the opening, terminal clips mounted on said door, and a fuse mounted between. last mentioned clips, said nrs-t mentioned clips engaging and pressing 70 said last mentioned clips against the fuse upon closure of the door.

6. In co ination, a tube of insulation, metallic end cs closing the ends thereof, insulating bushings extending into the tube through the end pieces, a resistor unit mounted at one end on one vbushing and having a terminal clip at its other end, a terminal clip at the end of the other bushing, said tube having an opening in the periphery thereof, a door closing the opening, terminal clips mounted on said door, and a fuse mounted between said last mentioned clips, said rst mentioned clips engaging and pressing said last mentioned clips against the fuse upon closure of the door, said bushings, fuse and resistor unit being in alignment.

7. In combination, a tube of insulation, means closing the ends thereof and including insulating bushings and conductors extending therethrough, terminal clips within the tube of insulation, said tube having an opening in the periphery thereof, a door closing said opening, contact clips mounted on said door, and a protecting device mounted between said contact clips, said terminal clips engaging and pressing said contact clips against the protecting device upon closure of the door and establishing a circuit between the conductors by way of said device.

8. In combination, a tube of insulation, means closing the ends thereof and including insulating bushings and conductors extending therethrough, terminal clips within the tube of insulation, said tube having an opening in the periphery thereof, a door closing said opening, Contact clips mounted on said door, and a projecting device mounted between said contact clips, said terminal clips engaging and pressing said contact clips against the protecting device upon closure of theI door and establishing a circuit between the conductors by way of said device, said terminal clips and Contact clips having cooperative means for retaining the door closed.

9. Protecting apparatus comprising a tube o1" insulation, capping means for the ends of the tube including bushings in alignment with one another, conductors extending through the bushings, said tube having a longitudinally extending opening` in the periphery thereof, a closure for the opening, a circuit protecting device carried by the closure and extending between and in alignment with the bushings when the closure is closed, and terminal clips mounted within the tube and establishing a circuit between the bushing conductors by way of the device when the closure is closed.

10. Protecting apparatus comprising a tube of insulation, capping means for the ends of the tube, including bushings and conductors extending through the bushings and in alignment with one another, said tube having a longitudinally extending opening in the periphery thereof, a closure for the opening, a circuit protecting device carried by the closure by means including Contact making members engaging the ends of the device, said device extending between and in alignment with the conductors when the closure is closed, and spring terminal clips mounted within the tube and connected with the respective conductors and engaging the contact making members when the closure is closed.

tubular housing of insulation, a cylindrical protective resistor mounted in said housing, a high tension liquid quenched fuse also mounted in said housing in series with the resistor, said housing having a removable side wall, and means on the removable wall for disconnecting the fuse when said side wall is removed.

13. In a device of the class described, a tubular shell of insulation, metal heads for the ends of the shell, said heads having aligned mounting brackets, tubular bushing type insulators extending axially through and supported in the heads and terminating a substantial distance inside the shell, caps for the inner ends of the insulators, spring jaws carried by said caps, conductors extending through said insulators and being connected to said spring jaws, said shell having an elongated opening in a. side thereof facing said spring jaws, a curved cover plate bearing a fuse mounting adapted to close said opening, said plate having guide means for guiding the plate into register with the opening, and a fuse carried by said fuse mounting on the cover plate and adapted to be connected between said spring jaws When the cover plate is brought into position to close the opening.

lll. In combination, a tubular sleeve of insulation, metal heads for the ends of the sleeve, bushing type insulators extending axially through the heads into the inside of the sleeve, fuse contacts carried on said bushings, conductors extending through the bushings and connected with said fuse contacts, sleeves of insulation covering said conductors and extending inside said bushings, line conductors joined to said first-named conductors, and a wrapping of insulation extending from said sleeves over said joints.

15. In a device of the class described, a tubular shell of insulation, conductors extending axially into said tubular shell from the ends thereof, fuse clips in said shell connected to said conductors, said shell having an opening in the side wall thereof along the central part of the shell only for insertion and removal of a fuse, a cover plate carrying a fuse, and a handle for said cover plate comprising a loop of insulation blankcd by a web extending from the body of the cover plate to the loop.

16. In combination, a substantially dust proof tubular housing of insulation having current conducting leads extending axially thereinto, a cylindrical protective resistor disposed coaxially in the housing, and a high tension fuse mounted substantially coaxially in said housing and being connected in series with the resistor and said leads.

17. In combination, a substantially dust proof tubular housing of insulation, leads extending axially into said housing, a cylindrical protective resistor mounted coaxially in the housing, a high tension fuse of the type employing arc extinguishing material acted upon by the arc to evolve a gaseous medium, said fuse being mounted substantially coaxially in the housing and being connected in series with the resistor and said leads, said housing having a removable side wall, and means on the removable wall for disconnecting the fuse when said side wall is removed.

18. In a device of the class described, the combina-tion of a tubular sleeve of insulation, metal head members having laterally extending bracket arms for mounting the device upon a support, with the sleeve spaced from said support, said heads having openings with tubular insulating bushings fixed in said openings, metal cap members mounted on the inner ends of said bushings, rodlike conductors extending from said cap members through Ithe bushings and providing external terminals, spring jaws mounted on said cap members, said sleeve having an oblong opening in the side thereof to expose said jaws, and a cover detached from said sleeve for closing said opening, said cover having means for carrying a protective fuse into and out of contact with said jaws.

19. In a device of the class described, the combination of a tubular sleeve of insulation, metal head members having laterally extending bracket arms for mounting the device upon a support, with the sleeve spaced from said support, said heads having openings with tubular insulating bushings iixed in said openings, metal cap members mounted on the inner ends of said bushings, rodlike conductors extending from said cap members through the bushings and providing external terminals, a cylindrical protective resistor member comprising a wire said resister member being supported on one of said cap members and having said wire resistance connected at its adjacent end to said one cap member, a spring jaw mounted on said resistor member and connected at the other end of said wire resistance, a spring jaw mounted on the other of said cap members, said sleeve having a lateral oblong opening for exposing said jaws, and a cover for closing said opening, said cover having means for carrying a fuse into and out of said jaws and having a projecting flange which guides the cover into place over the opening and the fuse into register with the jaws.

20. In a device of the class described, the combination of a cylindrical sleeve of insulation having a lateral opening, metallic heads for the sleeve, said heads having axial openings, insulating bushings fixed in said openings, said heads having supporting bracket portions for supporting the sleeve out of contact with a supporting member, one of said heads having a circular flange telescoping with the top of the tube and preserving the cylindrical form of the same, contact jaws mounted on said bushings, a fuse adapted to cooperate with said jaws, and a cover plate for said opening, said cover plate having means carrying said fuse into and out of engagement with said jaws.

2l. In a device of the class described, the combination of an elonga-ted tubular casing of insulation having an oblong side opening, leads entering the casing, terminal clips connected to the leads and mounted within the casing, and a cover for the opening separable from the casing, said cover having means for carrying a fuse to be connected between said clips, said cover having inwardly projecting tongue members which at their bases are of substantially the width of the opening and provide guiding edges converging from the base to the tip for guiding the fuse into connection with the clips.

22. In a device of the class described, the combination of a tubular casing of insulation having an oblong lateral opening, stationary terminal i clips mounted in the casing in register with the opening, a cover having margins adapted to overlap the opening, said cover being separable from the casing and having means for supporting a fuse in position to be introduced laterally into the opening, guiding tongues projecting from the inside of said cover for guiding said fuse into connecting engagement with said clips, said tongues comprising thin parallel plates of a width at their bases substantially equal to the width of the opening and having edges tapering toward each other from the base to the tip to guide the cover over the opening laterally and endwise and to 5 bring the fuse into register with the clips.

23. In a device of the class described, a housing comprising two laterally separable portions,

a pair of contact clips on the first portion, a pair o1" fuse clips on the second portion, wedge shaped 10 guiding means for guiding the second portion into regis-ter with the rst portion, each contact clip comprising a C-shaped spring having guiding wings upon its extremities, each of said fuse clips having spring jaws for holding a fuse ferrule between them and adapted to be externally embraced by the extremities of the corresponding contact clip.

24. In a device of the class described, a housing comprising two laterally separable por-tions, a pair of contact clips on the first portion, a pair of fuse clips on the second portion, wedge shaped guiding means for guiding the second portion into register with the rst portion, each contact clip comprising a C-shaped spring having guiding wings upon its extremities, each of said fuse clips having spring jaws for holding a iuse ferrule between them and adapted to be externally embraced by the extremities of the corresponding contact clip, each inse clip having lateral projections so spaced as to be engaged by the extremities of the corresponding contact clip when the two housing portions are brought together.

25. In a device of the class described, a tubular housing having a lateral opening, insulating bushings supported substantially coaxially in the ends oi said housing, conductors extending through. said bushings, U-shaped contact brackets mounted on the ends of said bushings, one leg of each bracket being connected to one of said n conductors respectively, and the other leg of each bracket comprising a pair of spring jaws, the spring jaws of both brackets facing said opening,

a cover for said opening, said cover having means for carrying a fuse into electrical engagement with said spring jaws, and guiding tongues at the ends of the cover adapted to project between the legs of the brackets when the cover is in place.

2i. In a device of the class described, an insula-ting support, a cooperating cover member, spring clips mounted on said support and having contact portions converging toward each other, each of said clips having wing-shaped guiding portions on the Contact portions thereof, fuse clips adapted to cooperate with said spring clips, said fuse clips being mounted on said cover mem- -ber and being adapted to carry a fuse, said fuse clips having substantially parallel side portions with lateral projections therefrom adapted to engage the flanks of the converging Contact portions to hold said cover in predetermined position with respect to said insulating support.

2'7. In combination, a pair of spring contact clips, insulating supporting means therefor, an insulating fuse support having fuse clips with 5 jaws adapted to hold the ierrules of a fuse between them, said contact clips each having opposed convergent con-taot portions with divergent guiding extremities, said fuse clips having lateral oppositely extending projections adapted to pass within the convergent contact portions of the contact clips -to provide a snap action upon inserting the fuse clips within the contact clips.

HUGH A. TRIPLE'I'I. '(5 

